Type coercion for ENV

env_types.rb

class << ENV
  def integer(key)
    if value = self[key]
      value.to_i
    end
  end

  def boolean(key)
    case value = self[key]
    when /true/i
      true
    when nil, "", /false/i
      false
    when /\A\d+\z/
      value != "0"
    else
      raise ArgumentError.new("Could not coerce #{value.inspect} (via ENV[#{key.inspect}]) to a boolean")
    end
  end
end